[bazel] add more documentation around our Bazel build

[ParkMyCar]

This PR adds more documentation for how Bazel is setup at Materialize. It's goal is to cover both building Rust crates with Bazel in general, and any parts of our setup specific to Materialize.

Rendered

Motivation

Knowledge sharing and redundancy

Checklist

• This PR has adequate test coverage / QA involvement has been duly considered. (trigger-ci for additional test/nightly runs)
• This PR has an associated up-to-date design doc, is a design doc (template), or is sufficiently small to not require a design.
• If this PR evolves an existing $T ⇔ Proto$T mapping (possibly in a backwards-incompatible way), then it is tagged with a T-proto label.
• If this PR will require changes to cloud orchestration or tests, there is a companion cloud PR to account for those changes that is tagged with the release-blocker label (example).
• If this PR includes major user-facing behavior changes, I have pinged the relevant PM to schedule a changelog post.

[ParkMyCar]

@ptravers @DAlperin @SangJunBak I tagged all of y'all in this PR because I think you either have experience with Bazel or have expressed interest in it. Please let me know if there's anything here that doesn't make sense, or there might be parts I'm missing!

[ptravers]

do we want to move to dwarf 5? it looks like it has native rust support and is the latest version supported in the clang frontend.

see: https://doc.rust-lang.org/stable/unstable-book/compiler-flags/dwarf-version.html
and: rust-lang/rust#136926

[ParkMyCar]

Nice! I think when I looked at this in the past -Zdwarf-version was still unstable. We could probably bump macOS to dwarf 4 but we should validate that PolarSignals supports dwarf 5 before we go that far.

I'll make these changes in a separate PR if it's okay with you!

[ptravers]

that makes sense!

[ptravers]

I added a ticket. don't feel the need to do this before your departure. we can follow up. cheers!

https://github.com/MaterializeInc/database-issues/issues/9312